1. Field of the Invention
The present invention relates to an image data processing apparatus, and more particularly to an image data processing apparatus which applies filter processing to color image data.
In recent years, there have been striking developments in television, color printing, and other color image media and demands have grown for greater diversification and higher quality of the color images in printer output and in displays given to the final users.
For example, when outputting original color image data input from a scanner or other input unit to a printer, various types of modification of image data, such as adding some shading of the original color image data so as to smooth it a bit, have been demanded.
In the field of image processing, the most basic type of image data processing technique for meeting the above demands is known as filter processing. The present invention mainly relates to an image data processing apparatus designed for such filter processing.
2. Description of the Related Art
As will be explained in further detail later with reference to the attached drawings, in the conventional image data processing apparatus, the original image data is taken out from an image storage unit and that original image data is subjected to filter processing by a filter selected by an indication from the operator. In this case, the filter is taken out from a filter storage unit.
In such a filter storage unit, conventionally, just one filter of each filter size has been allotted to one type of image processing. That is, before a certain image processing was started, if the operator indicated he wanted "sharpening", a filter of a small filter size was allotted and that filter size could not be changed until the image processing ended. In the same way, if the operator indicates "smoothing" at the start of a certain image processing, a filter of a large filter size had to be used until continuously the image processing ended.
However, users are increasingly interested in higher qualities of images along with the development of the color image media mentioned above and therefore it is becoming no longer possible to meet user demands with filter processing using a single filter for each type of image processing. That is, with the conventional type of filter processing in an image processing apparatus, there is the problem that it is not possible to select a suitable filter size in accordance with the properties of the picture expressed by the original image data.